1. Field of the Invention
The invention generally relates to a device for the perforation of skin and, more specifically, toward such a device that includes a lancet that is received in a housing and mounted to a spring-loaded lancet carrier.
2. Description of Related Art
Such a device is known in the prior art by the product name xe2x80x9cLanzer-5xe2x80x9d from Becton Dickinson, Oxford OX4 3LY, United Kingdom, or from EP 0 061 102. The known device is composed of a multiplicity of individual parts. It also has the disadvantage that blood may accumulate in a cap, which is intended for reuse and can be screwed onto the housing. Such blood accumulations are not acceptable for hygienic reasons. It is conceivable, furthermore, that impurities such as skin diseases may adhere to the outside of the cap and, therefore, transferred from one patient to the next.
In devices known from EP 0 838 195 A1 and from U.S. Pat. No. 4,653,513, the lancet carrier extends from the housing into a cap attached to the latter. The purpose of these devices is to draw or suction blood into the cap. Such devices are complicated, since a vacuum for suctioning the blood has to be generated with them. The devices must have a correspondingly leak-tight design.
U.S. Pat. No. 4,375,815 discloses an automatically retractable lancet device that is designed as a disposable part. When the device is thrown away, parts that could still be used, from a hygienic point of view, are also thrown away. The device is relatively costly, and causes unnecessary environmental pollution.
FR 2 508 305, DE 89 00 203 U1, DE Patent 459 483 and DE Patent 355 891, which relate to the technological background of the invention, are directed toward devices for the extraction of blood samples, in which there is no removable cap provided.
An object of the invention is to eliminate the disadvantages of the prior art. In particular, the present invention provides a device for the perforation of skin that can be produced simply, is as cost-effectively as possible, and can be operated hygienically.
According to the invention, a lancet carrier is guided displaceably in a cap capable of being fastened to the housing. It is thereby possible to design the cap and lancet carrier as disposable articles. All the parts coming into contact with the patient are thrown away after the skin has been perforated, allowing the device to be operated hygienically.
Advantageously, the lancet carrier rotationally symmetrical, and preferably has a piston-like first portion. The lancet may be provided at one end of the lancet carrier and a flange-like, radially continuous projection may be provided at the other end. Such a lancet carrier can be produced simply.
In further accordance with the present invention, the lancet carrier is guided in the cap in a corresponding cylindrically designed second portion. The cap expediently has a first orifice for connection to the housing and a second orifice for the passage of the lancet. The cap and/or the lancet carrier may be produced from injection-molded plastic. The second orifice may be closed by means of a plastic film that is preferably injected-molded on in one piece, thereby insuring that the lancet is not contaminated before use.
The cap is affixed to the housing, for example, by means of a bayonet fastening, a locking connection, or a thread. A simple fastening is thereby produced.
The element is advantageously designed such that, with the cap removed, the element can be pressed, against the biasing force of a spring, into the housing up to a prestressed first position and can be automatically interlocked there. By at least one button being actuated the interlock can be released, so that the element is moved into a second position. A particularly simple and cost-effective makeup of the device becomes possible as a result.
In the second position, expediently, a locking or clamping element provided on the element is interlocked or clamped together with a corresponding counter-locking or counter-clamping element provided at the other end of the lancet carrier. The lancet advantageously passes through the plastic film and projects beyond the circumferential edge of the second orifice.
During the removal of the cap, with lancet extended, from the housing, the lancet carrier can be retracted up to a stop by means of the element. After the lancet carrier rests against the stop, the connection formed between the locking or clamping element and the counter-locking or counter-clamping element is released. With the cap then having to be thrown away, the risk of injury by a lancet projecting beyond the edge of the second orifice is avoided.
For a further simplification of the device in terms of production, the element may also be produced from injection-molded plastic. Expediently, a locking spring is injection-molded on the element in a one-piece design.
In further accordance with the present invention, the element may be guided displaceably in a carrying element received in the housing. In this case, the spring is advantageously supported against a bottom of the carrying element, while a prolongation, which extends from the element, can engage through a bottom perforation a design corresponding to the prolongation and can be secured by a dovetailed means against passage through the perforation. The abovementioned features make it easier to assemble the device.
The carrying element expediently extends over the circumferential edge of the housing, so that the cap can be slipped onto the carrying element.